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Mysterious vanishing of my eigenvalues
Posted 21 juil. 2010, 17:13 UTC−4 3 Replies
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Hi everybody,
I would like use COMSOL using two application modes and three steps.
FIRST STEP
1) First I use PDE modes / Weak Form Subdomain / Eigenvalue analysis
This mode allowed me to solve my eigenproblem. The solver "eigenvalue" gave me the set of eigenvalues (lambda_i) / eigenmodes (u_i) of the problem.
2) Then I use solve / solver manager / stored solution (initial value). I choose the first eigenvalue (u_1 and lambda_1) to use in the second step (I store this particular solution).
SECOND STEP
I open the application mode PDE mode / PDE general Form
Using the solver "Time dependant" (because my second equation is time dependant), I solve my second equation using the previous solution stored (both u_1 and lambda_1).
The solver gave me the solution u2.
These two first steps work good.
THIRD STEP
In this last step I have to solve a last equation using the previous solutions (u2 from the second step , lambda_1 and u_1 from the first step)...
u2 and u_1 are available for this step but lambda_1 is not available ! in fact lambda_1 has been deleted by the second step. Thus I cannot make this third step...
How to keep lambda_i (en particular lambda_1) available for the third step ?
Thank you for your help
Mathias
I would like use COMSOL using two application modes and three steps.
FIRST STEP
1) First I use PDE modes / Weak Form Subdomain / Eigenvalue analysis
This mode allowed me to solve my eigenproblem. The solver "eigenvalue" gave me the set of eigenvalues (lambda_i) / eigenmodes (u_i) of the problem.
2) Then I use solve / solver manager / stored solution (initial value). I choose the first eigenvalue (u_1 and lambda_1) to use in the second step (I store this particular solution).
SECOND STEP
I open the application mode PDE mode / PDE general Form
Using the solver "Time dependant" (because my second equation is time dependant), I solve my second equation using the previous solution stored (both u_1 and lambda_1).
The solver gave me the solution u2.
These two first steps work good.
THIRD STEP
In this last step I have to solve a last equation using the previous solutions (u2 from the second step , lambda_1 and u_1 from the first step)...
u2 and u_1 are available for this step but lambda_1 is not available ! in fact lambda_1 has been deleted by the second step. Thus I cannot make this third step...
How to keep lambda_i (en particular lambda_1) available for the third step ?
Thank you for your help
Mathias
3 Replies Last Post 22 juil. 2010, 06:56 UTC−4
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Posted:
1 decade ago
Hi
It's useful to search the Forum, as I'm sure I have read this before, including with a "solution"
--
Good luck
Ivar
It's useful to search the Forum, as I'm sure I have read this before, including with a "solution"
--
Good luck
Ivar
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Posted:
1 decade ago
Hi Ivar,
Thank you for your answer...but...
I already consulted the forum using the filter by Topic and the COMSOL books. Unfortunately every posts that I found deals with two applications modes BUT only two steps. I have no problems for this...These topics are similar to my problem but do not allowed me to solve it up to the end (I use three step).
The really problem appears after the second step...The first solutions (only the eigenVALUES but not the eigenMODES stored using solver manager after the first step), found in the first step by the eigensolver, no longer exist and the third step is not possible...
How keep these eigenvalue ? It is strange because the eigenmodes u_i are again correctly stored after the second step but not the eigenvalue lambda_i !!
Thank you again !
Mathias
Thank you for your answer...but...
I already consulted the forum using the filter by Topic and the COMSOL books. Unfortunately every posts that I found deals with two applications modes BUT only two steps. I have no problems for this...These topics are similar to my problem but do not allowed me to solve it up to the end (I use three step).
The really problem appears after the second step...The first solutions (only the eigenVALUES but not the eigenMODES stored using solver manager after the first step), found in the first step by the eigensolver, no longer exist and the third step is not possible...
How keep these eigenvalue ? It is strange because the eigenmodes u_i are again correctly stored after the second step but not the eigenvalue lambda_i !!
Thank you again !
Mathias
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Posted:
1 decade ago
Hi
Well with Matlab, you can access the different solutions at will. With the at() and with() operators you can select the items within a solution, but how to select different stored solution is not clear for me in the GUI environment
--
Good luck
Ivar
Well with Matlab, you can access the different solutions at will. With the at() and with() operators you can select the items within a solution, but how to select different stored solution is not clear for me in the GUI environment
--
Good luck
Ivar